Methods for producing graphene from coal

ABSTRACT

A method of preparing graphene from coal can include thermally processing raw coal and, after the coal has been at least partially cooled from thermal processing, forming reduced graphene oxide from the coal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application a divisional of U.S. patent application Ser. No.16/230,318, filed on 21 Dec. 2018, titled “Methods of Producing GrapheneFrom Coal,” which claims the benefit of U.S. Provisional PatentApplication No. 62/610,037 filed on 22 Dec. 2017, titled “Methods forProducing Advanced Carbon Materials from Coal,” the disclosure of whichis incorporated herein, by reference, in its entirety.

BACKGROUND

Coal is a highly varied heterogeneous material that has been mined andprincipally used for three purposes over thousands of years: 1) thegeneration of thermal heat and power generation through incineration, 2)the production of steel and other metals by coking, and 3) theproduction of what are now widely known as “petrochemicals” throughpyrolysis or liquefaction. Despite the fact that coal has beenextensively used for thousands of years, more than 99% of it has beenincinerated to produce heat and power. This process is now widely knownto produce a host of adverse environmental and economic effects.

Additional uses of coal has been the topic of research for many years.The basic chemistry of coal was well understood by at least the earlytwentieth century. Significant research was conducted with the aim ofderiving liquid transportation fuels from coal in order to supplantpetroleum. One notable breakthrough was the development of theFischer-Tropsch process in Germany, around 1925, which convertedgasified coal into liquid hydrocarbons. Additionally, Sasol, a majorSouth African company, focused on the conversion of solid coal to liquidtransportation fuels via catalytic cracking. Similarly, the UnitedStates Department of Energy sought to develop coal-based transportationfuels as an alternative to petroleum-based fuels. However, due toresearch driven petroleum technology and the decreasing costs ofpetroleum, the use of coal to produce liquid transportation fuels atlarge scales never became economically feasible.

Although significant research has been conducted on coal liquefactionand the use of coal to form other products for more than a century, theability to produce high-value, high-performance carbon based productsfrom coal remains an open question. In recent years, carbon-basedtechnologies have come to the forefront, with rapid developments beingmade in the commercialization of advanced carbon materials such ascarbon fiber, graphene, and carbon nanotubes. As these advancedmaterials are increasingly used in mass produced, high volumeapplications, there is a need to quickly and economically supply largequantities of advanced carbon materials to manufacturers. Thus, whileimprovements in the derivation of fuels and other products from coal arebeing explored, there remains significant work to be done in developingprocesses to convert coal into the advanced carbon materials that willbe instrumental in the economy of the future.

SUMMARY

A method of producing graphene from coal includes thermally processingcoal at a temperature of at least about 300° F., and after the coal hasbeen at least partially cooled from thermal processing, forming reducedgraphene oxide from the coal.

In some cases, forming reduced graphene oxide from the coal can includeoxidizing the coal to form a coal oxide, centrifuging the coal oxide,collecting precipitate from the coal oxide after centrifuging, theprecipitate comprising graphene oxide, and reducing the graphene oxideto form reduced graphene oxide. Oxidizing the coal to form a coal oxideincludes mixing the coal with at least one of sulfuric acid, nitricacid, or potassium permanganate, or hydrogen peroxide to form the coaloxide. Mixing the coal with at least one of sulfuric acid, nitric acid,potassium permanganate, or hydrogen peroxide to form the coal oxide caninclude mixing the coal with at least one of sulfuric acid and nitricacid, stirring the coal mixed with at least one of the sulfuric acid andthe nitric acid, mixing potassium permanganate to the coal mixed with atleast one of the sulfuric acid and the nitric acid, stirring the coalmixed with the potassium permanganate and at least one of the sulfuricacid and the nitric acid, diluting, with water, the coal mixed with thepotassium permanganate and at least one of the sulfuric acid and thenitric acid to form a solution, mixing the solution with hydrogenperoxide, performing a first centrifugation of the solution mixed withthe hydrogen peroxide, after performing the first centrifugation,separating a supernatant of the solution mixed with the hydrogenperoxide from precipitate of the solution mixed with the hydrogenperoxide, the supernatant including the coal oxide.

The method can further include diluting, with water, the coal oxidebefore centrifuging the coal oxide. In some cases, reducing the grapheneoxide to form reduced graphene oxide includes sonicating the grapheneoxide, and hydrothermally treating the graphene oxide in a par reactorafter sonicating the graphene oxide. In some cases, thermally processingcoal at a temperature of at least about 300° F. includes heating thecoal to a first temperature not to exceed 350° F., transferring the coalto a mercury removal reactor, heating the coal in the mercury removalreactor to a second temperature of at least 500° F., and contacting thecoal with an inert gas to remove at least a portion of mercury presentin the coal. In some cases, forming reduced graphene oxide from the coalincludes forming the reduced graphene oxide from the coal at a reducedgraphene oxide yield rate of between approximately 10 weight percent andapproximately 20 weight percent of the coal. In some cases, formingreduced graphene oxide from the coal includes retaining a predeterminedamount of one or more impurity atoms present in the amount of coal inthe reduced graphene oxide. In some cases, the impurity atoms includeone or more of boron, nitrogen, and silicon.

A method of producing synthetic graphene can include beneficiating anamount of coal including one or more impurity atoms to remove apredetermined amount of the one or more impurity atoms therefrom,processing the beneficiated amount of coal to produce an amount of pitchfrom at least some of the amount of coal, and treating at least some ofthe amount of pitch to produce the synthetic graphene, wherein thesynthetic graphene includes a desired amount of the one or more impurityatoms. In some cases, the amount of pitch includes mesophase pitch. Insome cases, the impurity atoms include one or more of silicon, nitrogen,and boron. In some cases, the impurity atoms result in a predeterminedamount of point defects in the synthetic graphene.

A method of producing synthetic graphene can include thermallyprocessing an amount of coal to achieve a predetermined concentration ofone or more impurity atoms in the amount of coal, oxidizing at leastsome of the amount of coal to form a coal oxide including apredetermined concentration of one or more impurity atoms, andprocessing the coal oxide to form reduced graphene oxide including apredetermined concentration of one or more impurity atoms.

In some cases, the one or more impurity atoms occur naturally in theamount of coal. In some cases, the impurity atoms include one or more ofcadmium, selenium, boron, nitrogen, and silicon. In some cases, thepredetermined concentration of the impurity atoms in the reducedgraphene oxide is from about 0.1 atomic % to about 10 atomic %.

A synthetic graphene formed from an amount coal can include apredetermined amount of dopant atoms, the dopant atoms derived from theamount of coal. In some cases, the dopant atoms include one or more ofboron, nitrogen, and silicon. The synthetic graphene can further includea predetermined amount of point defects due to the one or more dopantatoms.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of the presentapparatus and are a part of the specification. The illustratedembodiments are merely examples of the present apparatus and do notlimit the scope thereof.

FIG. 1 illustrates a process flow diagram of an example of a method ofproducing advanced carbon materials from coal in accordance with thepresent disclosure.

FIG. 2 illustrates a process flow diagram of an example of a method ofproducing advanced carbon material from coal including a pyrolysisprocess in accordance with the present disclosure.

FIG. 3 illustrates a process flow diagram of an example of a method ofproducing advanced carbon material from coal including a directliquefaction process in accordance with the present disclosure.

FIG. 4 illustrates a process flow diagram of an example of a method ofproducing advanced carbon material from coal including an indirectliquefaction process in accordance with the present disclosure.

FIG. 5 illustrates a material flow diagram of an example of a method ofproducing advanced carbon materials from coal in accordance with thepresent disclosure.

FIG. 6 illustrates a process flow diagram of an example of a method ofproducing graphene from coal in accordance with the present disclosure.

FIG. 7 illustrates a process flow diagram of an example of a method ofproducing reducing graphene oxide from coal in accordance with thepresent disclosure.

FIG. 8A is a Raman spectroscopy graph of a sample of Monarch seam coalin accordance with the present disclosure.

FIG. 8B is a Raman spectroscopy graph of a sample of thermally-treatedMonarch seam coal in accordance with the present disclosure.

FIG. 8C is a Raman spectroscopy graph comparing the sample of Monarchseam coal of FIG. 8A to the sample of thermally-treated Monarch seamcoal of FIG. 8B in accordance with the present disclosure.

FIG. 8D is a Raman spectroscopy graph of a sample of graphene fromthermally-treated Monarch seam coal, in accordance with this disclosure.

Throughout the drawings, identical reference numbers designate similar,but not necessarily identical, elements.

DETAILED DESCRIPTION

As described below, advanced carbon materials can be produced from raw,mined coal. In some embodiments, raw coal can be transported to aprocessing facility which can then produce graphene or other advancedcarbon materials therefrom. The coal can then be beneficiated in orderto remove a desired amount of impurities, for example mercury, arsenic,cadmium, other heavy metals, water, and volatile compounds. In somecases, beneficiation can include heating the coal to remove theseimpurities. The beneficiated coal can then be processed to produce apitch, activated carbon, and/or other precursors or advanced carbonmaterials. The processing can include subjecting the beneficiated coalto a pyrolysis process, direct liquefaction process, indirectliquefaction process, or processing involving one or more membranes. Insome cases, these processes can produce byproducts, such as gases, solidchar, and coal liquid extract which themselves can be processed to formuseful materials, such as other advanced carbon materials. For example,solid char can be processed to form activated carbon, and coal liquidextracted can be processed to form aromatic compounds such as benzeneand paraxylene.

In some embodiments, the pitch produced by the processes describedherein can be an isotropic pitch, and can be converted to a mesophasepitch by processing as needed or desired. The pitch can then be treatedto produce one or more advanced carbon materials. In some cases, thepitch can be processes to form synthetic graphite, which can besubjected to further processing to form or produce synthetic graphenehaving one or more desired physical, chemical, and/or electricalproperties. In some cases the pitch can be spun to form carbon fibers.These advanced carbon materials can be subjected to further processing,or can be delivered to third parties for use, for example inmanufacturing. In some cases one or more advanced carbon materials canbe produced and combined to form secondary material, such as a carbonreinforced polymer.

In some embodiments, one or more gases can be generated or producedduring beneficiation, pitch production, and/or other coal processingsteps as described herein. In some cases, these gases can be captured orotherwise contained and/or used during the processes described herein.The gases captured during certain process steps can be used insubsequent process steps, for example in the production or refinement ofadvanced carbon materials as described herein. In some cases, gasesproduced by and a captured as part of the processes described herein canbe utilized by these same or subsequent processes in order to increasethe efficiency and/or cost effectiveness of said processes. In somecases, these gases can be used as in the formation of advanced carbonmaterials as described herein, for example as precursors to advancedcarbon materials. Thus, in some cases, gases produced by coal asdescribed herein can be used to form advanced carbon materials. In someembodiments, the captured gas or gases can comprise hydrogen and/orcarbon. In some cases, the captured gas or gases can comprise sulfur.Such gases can include, for example, H₂, CO₂, CO, CH₄, C₂H₄, C₃H₆,and/or other hydrocarbon gases.

In some embodiments, one or more of the processes or process stepsdescribed herein can utilize or be carried out in the presence of one ormore catalysts. For example, one or more process can include ahydrogenation catalyst. In some embodiments, the catalyst can comprise ametal, for example platinum. In some cases, the catalyst can be amulti-part catalyst, for example a catalyst comprising two or moremetals. In some cases, a catalyst can include a ceramic or mineralmaterial, for example a silicate material, such as an aluminosilicatematerial. In some cases, a catalyst can include any catalytic materialnow known or as can yet be discovered for use in processing coal.

In some embodiments, all of the beneficiation, processing, and treatmentsteps described herein can be performed at a single processing facility,for example a single processing plant or compound. However, in otherembodiments, one or more steps can be performed at separate facilitiesand the products of each step can be stored and transported between eachfacility. As used herein, the term processing facility can refer to oneor more laboratories, buildings, process flows, or other apparatuses atabout the same geographic location. For example, a processing facilitycan comprise a single building or factory complex at a single geographiclocation which comprises such equipment to perform the processes andmethods described herein.

The advanced carbon materials which can be produced by the processesdescribed herein can include, but are not limited to, graphene, carbonfibers, carbon foams, single-walled carbon nanotubes, multi-walledcarbon nanotubes, carbon megatubes, graphite, graphite nano-platelets,nanoribbons, nanobuds, fullerenes, such as buckminsterfullerene andmulti-cored fullerenes, quantum dots, activated carbon, and pyrolyzedcarbon. The advanced carbon materials produced by the processesdescribed herein can also include, but are not limited to resins andpolymers, such as polyacrylonitrile, polyurethane resins, cyanate esterresins, epoxy resins, methacrylate resins, polyester resins, and others.The advanced carbon materials produced by the processes described hereincan also include materials that can be used as precursors in theformation of other advanced carbon materials. In some cases, theseadvanced carbon materials can include alkanes, alkenes, and/or alkynes.In some cases, advanced carbon materials can comprise biologicallyuseful materials or biopolymers, such as proteins, amino acids, nucleicacids, collagen, chitosan, and/or sugars.

In some embodiments, coal can be provided by any method that is nowknown or that can be developed in the future. For example, coal isgenerally extracted from naturally occurring layers or veins, known ascoal beds or coal seams, by mining. Coal can be extracted by surfacemining, underground mining, or various other forms of mining. Typically,coal that has been extracted via mining, but has not been otherwiseprocessed is referred to as raw coal. In some embodiments, raw coal canbe provided to a processing facility and used to produce advanced carbonmaterials as described herein. In some cases, the raw coal can beextracted via a surface mining process, such as a high wall miningprocess, strip mining process, or contour mining process. In some cases,the raw coal can be extracted via an underground mining process, such asby a longwall mining process, continuous mining process, blast miningprocess, retreat mining process, or room and pillar mining process.

The raw coal can be mined or extracted from a location relatively nearto the processing facility. For example, the processing facility can belocated at, or near a coal extraction area. However, in other cases coalcan be extracted from any location and transported to the processingfacility. In some cases raw coal can be provided to the processingfacility as needed to produce a desired amount of advanced carbonmaterials. However, in some other cases, raw coal can be provided andstored at the processing facility until it is processed.

Coal can be ranked or graded based on its contents and properties.Although a variety of coal classification schemes exist, a generalmetamorphic grade is used herein to generally describe raw coal. Thesegrades are used generally to aid in the understanding of the presentdisclosure and are not intended to limit to types of coal which can beused to produce advanced carbon materials as described herein. Whilecertain classifications of coal can be preferable for use in theprocesses described herein, such processes are not strictly limited tothe discussed classifications of coal, if any. In some embodiments, thecoal utilized by the processes described herein can be lignite coal, andcan have a volatile content of greater than about 45 wt. %. In someembodiments, the coal can be sub-bituminous coal, bituminous coal,and/or anthracite coal. In some embodiments, the coal can be coalextracted from the Brook Mine near Sheridan, Wyo. In some cases, thepreferred coal for use in the processes described herein can be selectedby the skilled artisan. According to some embodiments, and asillustrated in FIG. 1, graphene or another advanced carbon material canbe produced from coal by a method or process 100 including:

providing coal to a processing facility at block 110;

beneficiating the coal via the processing facility at block 120 toremove a desired amount of water, metals, and/or other impurities fromthe coal;

processing at least some of the beneficiated coal via the processingfacility at block 130;

producing pitch, char, gases, and/or coal liquid extract at block 140;and

treating the pitch via the processing facility at block 150 to producethe graphene or other advanced carbon material.

Although the method 100 describes a process flow for producing a singletype of advanced carbon material via a processing facility, the method100 can be used to produce more than one type of advanced carbonmaterial via the processing facility. For example, the method 100 can beutilized to produce an amount of a first advanced carbon material andsubsequently used to produce an amount of a second, different advancedcarbon material. In some cases however, the processing facility can beable to produce two or more different types of advanced carbon materialsvia parallel processing utilizing the method 100. Further, whileproducing pitch, char, and/or coal liquid extract is described as aseparate block 140, the pitch, char, and/or coal liquid extract can beproduced as a result of blocks 120 and/or 130 and may not be a separateprocess step in and of itself.

As described herein, raw coal can be provided to a processing facilityat block 110 for use in the method 100. The processing facility can havethe capacity to store raw coal for use as needed, or can receive rawcoal as needed to produce a desired amount of advanced carbon material.As is well known in the art, coal can be provided via truck, train, orany other form of transportation. Further, the processing facility canbe situated at a coal extraction site, such that coal extraction sitecan be considered as part of the processing facility.

At block 120, the raw coal can be beneficiated to remove contaminants orimpurities such as water, heavy metals, and/or volatile compounds fromthe raw coal, thereby producing beneficiated or upgraded coal. In somecases, the beneficiation process can comprise heating the raw coal to adesired temperature for a first duration. In some embodiments,beneficiation can also include heating the raw coal to a second, higherdesired temperature of a second duration. In some embodiments, the coalcan be heated in an atmosphere comprising a halogen gas. In someembodiments, beneficiation can include subjecting the raw coal to aWRITECoal beneficiation process, as described, for example, in U.S. Pat.No. 9,181,509 which is hereby incorporate by reference in its entirety.In some other embodiments, the coal can be beneficiated by heating thecoal to a desired temperature in the presence of one or more catalystcompounds. In some cases, beneficiating the coal can comprise pyrolyzingthe coal, for example in the presence of a catalyst. In some cases, thecoal can be beneficiated by the BenePlus System, as developed andlicensed by LP Amina and as described, for example, in U.S. PatentPublication No. 2017/0198221 which is hereby incorporated by referencein its entirety.

The beneficiated coal can comprise a significantly reduced amount ofmercury, cadmium, other heavy metals, water, and/or other impurities. Asused herein, an impurity can be considered any element or compound otherthan carbon or hydrogen. For example, beneficiating the coal can reducethe amount of mercury in the coal by about at least about 70%, 75%, 80%,85%, 90%, or 92% or more. In some cases, beneficiating the coal canreduce the water or moisture content of the coal to less than about 5wt. %, 4 wt. %, 3 wt. %, 2 wt. %, or 1.5 wt. % or lower. In some cases,beneficiating the coal can remove one or more of hydrogen, sulfur,oxygen, arsenic, selenium, cadmium, or volatile matter from the coal.The amount of one or more of these elements in the coal can be reducedby from about 25% to about 90%.

However, in some cases it can be desirable for a desired amount of oneor more impurities to remain in the beneficiated coal after beingsubjected to a beneficiation process. For example, in some embodiments abeneficiation process can remove a desired amount of impurities suchthat a predetermined amount of cadmium, selenium, or another element canremain in the beneficiated coal after processing. In some cases, thedesired amount of impurity that can remain in the coal afterbeneficiation can be useful in the subsequent formation of advancedcarbon materials, and/or can be incorporated into the advanced carbonmaterials. For example, in some embodiments where the advanced carbonmaterial comprises synthetic graphene, a desired amount of cadmium canremain in the beneficiated coal and can be incorporated into thesynthetic graphene to thereby improve the electrical, mechanical, orchemical properties thereof.

In some embodiments, beneficiating the coal can produce various otherproducts that can be captured and used in later processing steps, thatcan be valuable in and of themselves, or that can be subjected tofurther processing or use in the method 100. That is, in someembodiments, beneficiating the coal can produce or separate gases orliquids from the raw coal. These gases and/or liquids can be captured orseparated during processing. For example, beneficiating the coal atblock 120 can produce H₂, CO₂, CO, CH₄, C₂H₄, C₃H₆, and/or otherhydrocarbon gases, which can be captured and subsequently utilized inblock 130 or in other process steps. In some cases, beneficiating thecoal can result in liquids such as toluene or benzene which can becaptured for subsequent use or processing. In some cases, the impuritiesremoved from the coal by the beneficiation process at block 120 can becaptured for subsequent use. For example, water removed from the coal bythe beneficiation process can be capture and utilized in subsequentprocess steps. In some embodiments, beneficiating the coal can alsoproduce a solid material known as ash or char. In some cases, this charcan be subjected to further processing to form activated ca

At block 130 the beneficiated coal, also referred to as upgraded coal,can be processed via the processing facility. In some embodiments,processing the beneficiated coal can include subjecting the upgradedcoal to a liquid extraction process, such as a pyrolysis process, adirect liquefaction process, an indirect liquefaction process, or aprocess including one or more membranes.

In some embodiments, block 130 can comprise pyrolyzing the beneficiatedcoal via the processing facility. In some embodiments pyrolyzing thebeneficiated coal can comprise heating the coal above a desiredtemperature for a duration. In some cases, the coal can be heated athigh pressure and in the presence of a solvent. For example, theupgraded coal can be pyrolyzed in the presence of a CO₂ solvent whichcan be held in a supercritical state. In some cases, the upgraded coalcan be pyrolyzed by the MuSCL System developed by TerraPower asdescribed, for example, in U.S. Pat. No. 10,144,874 which is herebyincorporate by reference in its entirety.

In some embodiments, the pyrolysis process can comprise exposing theupgraded coal to electromagnetic radiation at a desired intensity andfor a desired duration. For example, block 130 can comprise exposing theupgraded coal to microwave and/or radiofrequency (RF) radiation for adesired duration as part of the pyrolysis process. In some cases, thispyrolysis process can result in the bulk of the upgraded coal remainingbelow pyrolytic temperatures, while individual particles of coal can besubjected to temperatures greater than about 1200° F. In some cases,this pyrolysis process can also comprise methane activation and/ormethylation of at least some of the carbon comprising the upgraded coal.In some embodiments, the upgraded coal can be pyrolyzed by the WaveLiquefaction process developed by H Quest Vanguard, Inc. as described,for example, in U.S. Patent Publication No. 2017/0080399 which is herebyincorporate by reference in its entirety.

In some embodiments, block 130 can comprise subjecting the upgraded coalof block 120 to a liquefaction process. In some embodiments, theliquefaction process can be a direct liquefaction process. In some otherembodiments, the liquefaction process can be an indirect liquefactionprocess.

In some cases where block 130 comprises a direct liquefaction process,the upgraded coal can be heated above a desired temperature for aduration. In some cases, the upgraded coal can be heated in the presenceof one or more catalysts and/or at an elevated pressure. In some cases,the upgraded coal can be heated in an atmosphere comprising H₂. In somecases, the direct liquefaction process can be a hydrogenation orhydro-cracking process. In some cases, the upgraded coal can besubjected to a direct liquefaction process developed by Axens asdescribed, for example, in U.S. Patent Publication No. 2017/0313886which is hereby incorporated by reference in its entirety.

In some embodiments, block 130 can comprise an indirect liquefactionprocess, where the upgraded coal can be converted to a gas or gases,which can then be converted to one or more liquids. For example, anindirect liquefaction process can include heating the upgraded coal to adesired temperature for a desired duration at a desire pressure, such asan elevated pressure. In some cases, this can convert at least some ofthe upgraded coal to a gas or gases, such as syngas, a mixture of H₂ andCO gas. In some cases, these gases, such as syngas, can then beconverted to liquids or other materials. For example, the syngas can beconverted to ammonia or methanol, which can in turn be subjected tofurther processing to produce hydrocarbons. In some cases, the gases canbe processed to ultimately produce olefins, such as ethylene andpropylene. In some cases, the gases can be processed to producehydrocarbons, such as aromatic hydrocarbons. In some cases, the gasescan be processed to produce hydrocarbons such as toluene, benzene,paraxylene, or other hydrocarbons, including polymers and resins. Insome cases, the gases can be converted to olefins by a process developedby Honeywell UOP as described, for example, in U.S. Patent PublicationNo. 2015/0141726 which is hereby incorporated by reference in itsentirety. In some cases, the upgraded coal can be subjected to anindirect liquefaction process.

In some embodiments, block 130 can comprise processing the beneficiatedcoal in the presence of one or more membranes. In some cases, thesemembranes can serve to physically and/or chemically separate and/orcrack the beneficiated coal to produce products therefrom. In somecases, these products can be substantially similar to the productsproduced by a liquefaction process, but may not use the amount of heator pressure that a liquefaction process can require. Thus, in somecases, processing beneficiated coal with one or more membranes canproduce substantially similar products to a liquefaction process but canrequire substantially less energy to do so. In some embodiments, the oneor more membranes can comprise various pore sizes, chemical properties,physical properties, or electrical properties to isolate desirablecompounds and/or produce desirable compounds from the beneficiated coal.

In some embodiments, one or more additives can be added to thebeneficiated coal at block 140. In some embodiments, one or more othergases or liquids can be used during the processes of block 140. Forexample, hydrogen containing gases can be added to or used during a coalliquefaction process. In some cases, natural gases, CO₂, or petroleumproducts can be used as additives during block 130. In some embodiments,the one or more additives can include materials or compounds that areproduced during blocks 120 and/or 130, or that can be produced by orcaptured during previous iterations of process 100.

At block 140, pitch, char, gases, and/or coal liquid are produced viathe processing facility. The skilled artisan will appreciated that block140 can represent the result of blocks 120 and 140, rather than aseparate action or process step. While the blocks 110-150 togetherdefine the method 100, the method can include additional steps asdescribed herein.

In some embodiments, pitch can be produced via the processing facilityat block 140. As used herein, pitch, also known as coal pitch, coal tar,or coal tar pitch, can refer to a mixture of one or more typicallyviscoelastic polymers as will be well understood by the skilled artisan.In some embodiments, the pitch produced at block 140 can be a directresult of processing the beneficiated coal at step 130. The pitchproduced at block 140 can comprise one or more high molecular weightpolymers. In some embodiments, the pitch can have a melting point ofgreater than about 650° F. In some embodiments, the pitch can have amelting point that is high enough that the pitch can be used in a carbonfiber spinning process, for example as described herein, without theneed for a plasticizer.

In some embodiments, the pitch can comprise aromatic hydrocarbons, forexample polycyclic aromatic hydrocarbons. In some cases, the pitch cancomprise at least about 50 wt. % polycyclic aromatic hydrocarbons, atleast about 60 wt. %, 70 wt. %, 80 wt. %, 90 wt. %, 95 wt. %, or 99 wt.% or greater of polycyclic aromatic hydrocarbons. In some embodiments,the pitch can be relatively free of impurities, such as water,non-carbon atoms including sulfur or nitrogen, or material such as coalash or char. In some cases, the pitch can comprise less than about 0.2wt. % water, less than about 0.1 wt. %, less than about 0.05 wt. %, orless than about 0.01 wt. % water or lower. In some cases, the pitch cancomprise less than about 0.1 wt. % ash or other solid material, lessthan about 0.05 wt. % ash or solid material, or less than about 0.01 wt.% ash or solid material. In some cases, the pitch can have a flash pointgreater than about 230° F., greater than about 250° F., or greater thanabout 300° F. In some cases, the pitch can have an API gravity of lessthan about 4, less than about 3, or less than about 2, or less. In someembodiments, the pitch can have a hydrogen to carbon (H:C) ratio ofabout 1:1. In some embodiments, the pitch can be an isotropic pitch. Insome embodiments, the pitch produced by the method 100 is not cokepitch. That is, in some cases, the pitch produced at block 140 is notproduced from coke or a coke based material. In some embodiments, cokeis not produced at any point during the method 100.

In some embodiments, char can be produced via the processing facility atblock 140. As used herein, char, also known as ash, can refer to anysolid material which remains after gases, liquids, and/or pitch havebeen removed from raw coal. For example, in some embodiments, char canbe produced during the beneficiation of raw coal at block 120. In someembodiments, char can be produced by the processing of block 130. Insome embodiments, char can be produced as a result of blocks 120 and130.

In some embodiments, char can comprise a solid high surface areacarbonaceous material. In some cases, char can have a relatively low H:Cratio, for example lower than the H:C ratio of pitch produced at block140. In some cases, char can have an H:C ratio of from about 0.05 toabout 0.65. In some cases, char can additionally comprise at least somepitch material, which can be referred to herein as intrinsic binderimpregnation. In some cases, any residual pitch or other gaseous orliquid materials can be removed from the char prior to any subsequentprocessing of the char.

In some embodiments, any char produced at block 140 can be subjected tofurther processing, for example to produce an advanced carbon materialsuch as activated carbon. In some cases, char can be carbonized orheated, for example in a rotary kiln, as part of this furtherprocessing. In some cases the char can then be activated, for examplevia a physical activation process or a chemical activation process. Insome cases, physical activation can comprise heating the char in anatmosphere comprising argon and/or nitrogen, or heating the char in anoxidizing atmosphere. In some cases, chemical activation can compriseimpregnating the char with one or more chemicals, such as an acid, abase, or a salt. In some cases, chemical activation can further comprisecarbonizing or heating the impregnated char to activate it. In somecases, chemical activation can require lower temperatures and lessenergy than physical activation. Further, in some cases, chemicalbyproducts produced by the method 100 can be utilized during thechemical activation process.

In some embodiments, one or more liquids can be produced via theprocessing facility at block 140. These liquids are referred tocollectively as coal liquid extracts herein, and can refer to anymaterial that is extracted or produced from raw coal and is liquid at ornear normal temperature and pressure (about 68° F. and 1 atmosphere ofpressure). For example, in some embodiments, coal liquid extracts can beproduced during the beneficiation of raw coal at block 120. In someembodiments, coal liquid extracts can be produced by the processing ofblock 130. In some embodiments, coal liquid extracts can be produced asa result of blocks 120 and 130.

In some embodiments, one or more gases can be produced via theprocessing facility at block 140 and can be captured for later use orreuse. In some embodiments, these gases can be produced during thebeneficiation of raw coal at block 120. In some embodiments, gases canbe produced by the processing of block 130. In some embodiments, gasescan be produced as a result of blocks 120 and 130. In some embodiments,the captured gas or gases can comprise hydrogen and/or carbon. In somecases, the captured gas or gases can comprise sulfur. Such gases caninclude, for example, H₂, CO₂, CO, CH₄, C₂H₄, C₃H₆, and/or otherhydrocarbon gases. As described herein, in some cases, the capturedgases produced by the method 100 can themselves be used as precursors toform advanced carbon materials.

In some embodiments, coal liquid extracts can comprise one or moreliquid hydrocarbons. For example, coal liquid extracts can comprise oneor more of benzene, toluene, alkanes or paraffins, alkenes, or othersaturated or unsaturated hydrocarbons. In some embodiments, coal liquidextracts produced at block 140 can be subjected to further processing,for example to refine or isolate specific liquids, or to convert coalliquid extracts to other liquid compounds. For example, the coal liquidextracts can be subjected to a process to convert one or more of thecoal liquid extracts to benzene and/or paraxylenes. In some cases, thecoal liquid extracts can be subjected to processing to produce advancedcarbon material, such as resins or polymers. In some cases, the coalliquid extracts can be processed to form polyurethane resins, cyanateester resins, epoxy resins, methacrylate resins, polyester resins, andothers.

Pitch, char, gases, and coal liquid extracts are all described as beingproduced at block 140, however in some embodiments, one or more of theseproducts can be produced at separate times or separate processing stepsfrom any other product. In some embodiments, one or more of pitch, char,and coal liquid extracts can be produced together by a process step andcan need to be separated before any further processing of eachindividual product can occur. For example, pitch and coal liquidextracts can be simultaneously produced as a result of block 130 and canneed to be separated from one another, by any process now know or whichcan be developed in the future, before further processing of eitherpitch or coal liquid extracts occurs. Accordingly, the method 100 cancomprise a further step of separating one or more of the pitch, char,and coal liquid extracts from each other prior to block 150.

At block 150, the pitch produced at block 140 can be treated via theprocessing facility to produce one or more advanced carbon materialsdescribed herein. In some embodiments, the pitch of block 140 is notsubjected to further processing or refinement to alter the chemicalcomposition of the pitch before being treated to form an advanced carbonmaterial. However, in some other embodiments, the pitch can be subjectedto one or more processes which can alter the chemical composition of thepitch prior to block 150. For example, impurities can be removed fromthe pitch prior to block 150. In some cases, the pitch can be subjectedto one or more processes to produce mesophase pitch or otherwise alterthe composition or properties of the pitch

In some embodiments, block 150 can comprise processing the pitch to formsynthetic graphite. In some cases, the synthetic graphite can besubjected to further processing to form synthetic graphene. For example,in some embodiments block 150 can comprise treating the pitch, forexample by exposure to heat, elevated pressure, and/or one or morecatalysts to form synthetic graphite. As used herein, the term syntheticgraphite is used to refer to any graphite material produced from aprecursor material, for example any graphite material that does notoccur naturally in the earth. In some embodiments, block 150 can furthercomprise treating or processing the synthetic graphite to form syntheticgraphene. As used herein, synthetic graphene refers to any graphenematerial produced or derived from synthetically formed graphite. Forexample, block 150 can comprise subjecting the synthetic graphite tomechanical exfoliation to produce synthetic graphene.

In some embodiments, the method 100 can further comprise capturing atleast some of the gases, liquids, or other volatile compounds which canbe produced as a result of the method, 100, including blocks 110-150. Insome embodiments at least 50%, at least 75%, at least 90%, 95%, or 99%of any gaseous or volatile byproducts of the method 100 can be captured.In some cases, some or all of these captured or retained gaseous orvolatile byproducts can then be used in the steps of the method 100. Forexample, CO₂ gas can be produced by one or more of the steps of method100, which can be captured and subsequently used in any of the steps ofmethod 100. In some cases, the capture and reuse of byproducts canimprove the efficiency and/or lower the cost of the method 100.

According to some embodiments, an advanced carbon material can beproduced from coal by a method or process including:

providing coal to a processing facility;

beneficiating the coal via the processing facility to remove a desiredamount of water, metals, volatile compounds, and other impurities fromthe coal;

processing at least some of the beneficiated coal via the processingfacility;

producing pitch, char, gases, and/or coal liquid extract; and

treating one or more of the pitch, char, gases, and/or coal liquidextract via the processing facility to produce one or more advancedcarbon materials.

According to some embodiments, and as illustrated in FIG. 2, an advancedcarbon material can be produced from coal by a method or process 200including:

providing coal to a processing facility at block 210;

beneficiating the coal via the processing facility at block 220 toremove a desired amount of water, metals, and other impurities from thecoal;

pyrolyzing at least some of the beneficiated coal via the processingfacility at block 230;

producing pitch, char, gases, and/or coal liquid extract at block 240;and

treating at least one of the pitch, char, gases, and coal liquid extractvia the processing facility at block 250 to produce the advanced carbonmaterial. Although the method 200 describes a process flow for producinga single type of advanced carbon material via a processing facility, themethod 200 can be used to produce more than one type of advanced carbonmaterial via the processing facility. For example, the method 200 can beutilized to produce an amount of a first advanced carbon material andsubsequently used to produce an amount of a second, different advancedcarbon material. In some cases however, the processing facility can beable to produce two or more different types of advanced carbon materialsvia parallel processing utilizing the method 200. Further, whileproducing pitch, char, gases, and/or coal liquid extract is described asa separate block 240, the pitch, char, gases, and/or coal liquid extractcan be produced as a result of blocks 220 and/or 230 and may not be aseparate process step in and of itself.

According to some embodiments, and as illustrated in FIG. 3, an advancedcarbon material can be produced from coal by a method or process 300including:

providing coal to a processing facility at block 310;

beneficiating the coal via the processing facility at block 320 toremove a desired amount of water, metals, and other impurities from thecoal;

subjecting at least some of the beneficiated coal to a directliquefaction process via the processing facility at block 330;

producing pitch, char, gases, and/or coal liquid extract at block 340;and

treating at least one of the pitch, char, gases, and coal liquid extractvia the processing facility at block 350 to produce the advanced carbonmaterial.

Although the method 300 describes a process flow for producing a singletype of advanced carbon material via a processing facility, the method300 can be used to produce more than one type of advanced carbonmaterial via the processing facility. For example, the method 300 can beutilized to produce an amount of a first advanced carbon material andsubsequently used to produce an amount of a second, different advancedcarbon material. In some cases however, the processing facility can beable to produce two or more different types of advanced carbon materialsvia parallel processing utilizing the method 300. Further, whileproducing pitch, char, gases, and/or coal liquid extract is described asa separate block 340, the pitch, char, gases, and/or coal liquid extractcan be produced as a result of blocks 320 and/or 330 and may not be aseparate process step in and of itself. According to some embodiments,and as illustrated in FIG. 4, an advanced carbon material can beproduced from coal by a method or process 400 including:

providing coal to a processing facility at block 410;

beneficiating the coal via the processing facility at block 420 toremove a desired amount of water, metals, and other impurities from thecoal;

subjecting at least some of the beneficiated coal to an indirectliquefaction process via the processing facility at block 430;

producing pitch, char, gases, and/or coal liquid extract at block 440;and

treating at least one of the pitch, char, gases, and coal liquid extractvia the processing facility at block 450 to produce the advanced carbonmaterial.

Although the method 400 describes a process flow for producing a singletype of advanced carbon material via a processing facility, the method400 can be used to produce more than one type of advanced carbonmaterial via the processing facility. For example, the method 400 can beutilized to produce an amount of a first advanced carbon material andsubsequently used to produce an amount of a second, different advancedcarbon material. In some cases however, the processing facility can beable to produce two or more different types of advanced carbon materialsvia parallel processing utilizing the method 400. Further, whileproducing pitch, char, gases, and/or coal liquid extract is described asa separate block 440, the pitch, char, gases, and/or coal liquid extractcan be produced as a result of blocks 420 and/or 430 and may not be aseparate process step in and of itself.

FIG. 5 illustrates a material flow diagram of an example of a method 500of producing one or more advanced carbon materials from coal inaccordance with the present disclosure. At block 510, raw coal isprovided to a processing facility, for example by a mining process, suchas high wall mining. The raw coal can then be subjected to abeneficiation process to remove a desired amount of water, metals,volatile matter, and other impurities as described herein at block 520.In some cases, the beneficiation process can produce byproducts, such aschar (block 542) and gases and/or coal liquid extracts (546), inaddition to the upgraded coal. The upgraded coal can be subjected to apyrolysis, direct liquefaction, or indirect liquefaction process atblock 530 and as described herein to produce pitch (block 540). Again,in some cases, the pyrolysis or liquefaction process of block 540 canproduce byproducts, such as char (block 542) and coal liquid extractsand gases (block 546). In some cases, the char 542 can be processed ortreated at block 560 to produce an advanced carbon material, for exampleactivated carbon (block 544) as described herein. In some cases, thecoal liquid extract 546 can be processed or treated at block 570 toproduce hydrocarbons, such as benzene and paraxylenes and/or otheradvanced carbon materials (block 548) as described herein. At block 550,the pitch can be processed or treated to produce one or more advancedcarbon materials (block 580), such as carbon fibers or graphene asdescribed herein.

In some embodiments, the method 500 can be entirely carried out at asingle processing facility. However, in some other cases, one or moreblocks can be carried out at different processing facilities and/ordifferent locations. For example, char 542 or coal liquid extract 546can be transported to a second location where blocks 560 and 570 can becarried out.

Although the processes described herein relate to the production ofadvanced carbon materials from coal, in some embodiments these processescan be utilized to produce silicon products, such as silicone resins.For example, in some embodiments, sand or other raw materials comprisingsilicon can be used in the processes and methods described herein toproduce one or more silicone resins.

According to some embodiments, and as illustrated in FIG. 6, syntheticgraphene can be produced from coal by a method or process 600 including:

providing coal to a processing facility at block 610;

beneficiating the coal via the processing facility at block 620 toremove a desired amount of water, mercury, cadmium, selenium, otherheavy metals, and/or other impurities from the coal;

processing at least some of the beneficiated coal via the processingfacility at block 630;

producing pitch, char, gases, and/or coal liquid extract at block 640;and

treating at least one of the pitch, char, gases, and coal liquid extractvia the processing facility at block 650 to produce synthetic graphite;

treating the synthetic graphite via the processing facility at block 660to produce the synthetic graphene.

As described herein, a desired amount of one or more impurities canremain in the beneficiated coal at block 620 and can thereby beincorporated into the synthetic graphene produced at block 660 in orderto adjust the chemical, electrical, and/or physical properties of thesynthetic graphene.

According to some embodiments, and as illustrated in FIG. 7, graphene oranother advanced carbon material can be produced from coal by a methodor process 700 including thermally processing coal at block 710 andforming reduced graphene oxide from the coal after the coal has been atleast partially cooled from thermal processing. Forming reduced grapheneoxide from the coal can include: oxidizing the coal at block 720 to formcoal oxide; centrifuging the coal oxide at block 730; collectingprecipitate from the coal oxide after centrifuging at block 740, theprecipitate including graphene oxide; and reducing the graphene oxide atblock 750 to produce reduced graphene oxide. In other embodiments, otheractivities can be used to form graphene from the thermally-treated coal,such as chemical vapor deposition or formation of carbon dots.

Although the method 700 describes a process flow for producing graphene,the method 700 can be used to produce more than one type of advancedcarbon material. For example, the method 700 can be utilized to producean amount of a first advanced carbon material and subsequently used toproduce an amount of a second, different advanced carbon material. Insome cases however, two or more different types of advanced carbonmaterials can be produced via parallel processing utilizing the method700. Further, various steps of method 700 can each include multiplesteps, and various steps of method 700 may not be a separate processsteps in and of themselves.

The coal that is thermally processed at block 710 can include raw coal,as described in greater detail above, or coal that is at least partiallyprocessed. The raw or at least partially processed coal can include coalcrushed to a suitable or predetermined size. Thermally processing thecoal can include beneficiating the coal to remove contaminants orimpurities, as described above in greater detail. Thermally processingthe coal according to this disclosure also can include any of theactivities described in U.S. Pat. No. 5,403,365, the disclosures ofwhich are incorporated herein by reference.

In many embodiments, thermally processing coal can include thermallyprocessing coal at a temperature of at least about 300° F. Moreparticularly, in some embodiments, thermally processing coal can includeheating the coal to a first temperature not to exceed 350° F.,transferring the coal to a mercury removal reactor, heating the coal inthe mercury removal reactor to a second temperature of at least 500° F.,and contacting the coal with an inert gas to remove at least a portionof mercury present in the coal.

In some embodiments, heating the coal to a first temperature not toexceed 350° F. includes heating the coal to a first temperature not toexceed between about 250° F. and about 350° F., between about 275° F.and about 325° F., between about 285° F. and about 315° F., betweenabout 295° F. and about 305° F., between about 295° F. and about 300°F., between about 300° F. and about 305° F., about 290° F., about 295°F., about 300° F., about 301° F., about 302° F., about 303° F., about304° F., about 305° F., about 310° F., about 315° F., about 320° F.,about 325° F., about 330° F., about 335° F., about 340° F., about 345°F., or about 350° F. When the coal is heated to the first temperature,free water and at least a portion of bound water in the coal isvaporized and removed in a sweep gas. In some embodiments, the coal canbe heated in a moisture removal reactor and/or a vibrating fluidized-bedsystem. Dryer auxiliaries in the moisture removal reactor can include ahot gas generator, a coal feeder, and valves.

After heating the coal to the first temperature, the coal can betransferred to a mercury removal reactor, where the coal can be heatedto a second temperature of at least 500° F. In some embodiments, thecoal can be heated in the mercury removal reactor to a temperature ofbetween about 400° F. and about 700° F., between about 450° F. and about650° F., between about 500° F. and about 600° F., between about 525° F.and about 575° F., between about 535° F. and about 570° F., betweenabout 540° F. and about 565° F., between about 545° F. and about 560°F., between about 550° F. and about 555° F., at least about 500° F., atleast about 510° F., at least about 520° F., at least about 530° F., atleast about 540° F., at least about 545° F., at least about 550° F., atleast about 555° F., about 550° F., about 551° F., about 552° F., about553° F., about 554° F., about 555° F., about 556° F., about 557° F.,about 558° F., about 559° F., or about 560° F.

A down-flow reactor can be used to expose the coal to a hot inert gas,which volatizes and removes at least a portion of the mercury and/or atleast a portion of one or more dopants. For example, between about 70%and about 80% of the mercury in the coal can be volatized and removedfrom the coal. In some cases, other dopants or impurities can be removedfrom the coal, for example, cadmium, selenium, and/or any other elementexcept carbon which may be present in the coal. The coal also can becooled to a third temperature in the mercury removal reactor, the thirdtemperature being below about 400° F., below about 375° F., below about350° F., below about 325° F., below about 300° F., below about 275° F.,or below about 250° F. Upon cooling to the third temperature, the coalcan be reduced in size before forming reduced graphene oxide from thecoal.

As noted above, forming reduced graphene oxide from the coal caninclude: oxidizing the coal at block 720 to form coal oxide;centrifuging the coal oxide at block 730; collecting precipitate fromthe coal oxide after centrifuging at block 140, the precipitateincluding graphene oxide; and reducing the graphene oxide at block 150to produce reduced graphene oxide. At block 720, oxidizing the coal toform a coal oxide can include mixing the coal with at least one ofsulfuric acid, nitric acid, or potassium permanganate, or hydrogenperoxide to form the coal oxide. In some embodiments, mixing the coalwith at least one of sulfuric acid, nitric acid, potassium permanganate,or hydrogen peroxide to form the coal oxide can include: mixing the coalwith sulfuric acid and then mixing nitric acid with the mixture of coaland sulfuric acid.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include stirring the mixture of coal, sulfuric acid, andnitric acid for a predetermined period of time. For example, in someembodiments, the mixture of coal, sulfuric acid, and nitric acid can bestirred for at least about 1 hour, at least about 2 hours, at leastabout 3 hours, at least about 4 hours, at least about 5 hours, betweenabout 1 hours and about 5 hours, between about 2 hours and about 4hours, between about 2.5 hours and about 3.5 hours, about 1 hour, about2 hours, about 3 hours, about 4 hours, about 5 hours, less than about 1hour, less than about 2 hours, less than about 3 hours, less than about4 hours, or less than about 5 hours.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include, after stirring the mixture of coal, sulfuricacid, and nitric acid, mixing potassium permanganate to the mixture ofcoal, sulfuric acid, and nitric acid and then stirring the mixture ofcoal, sulfuric acid, nitric acid, and the potassium permanganate for apredetermined period of time. In some embodiments, the mixture of coal,sulfuric acid, nitric acid, and the potassium permanganate can bestirred on a hot plate heated to between about 25° C. and about 45° C.,between about 30° C. and about 40° C., between about 33° C. and about37° C., at least about 25° C., at least about 30° C., at least about 35°C., at least about 40° C., at least about 45° C. about 25° C., about 30°C., about 35° C., about 40° C., or about 45° C. In some embodiments, themixture of coal, sulfuric acid, nitric acid, and the potassiumpermanganate can be stirred for at least about 1 hour, at least about 2hours, at least about 3 hours, at least about 4 hours, at least about 5hours, at least about 6 hours between about 1 hours and about 6 hours,between about 3 hours and about 5 hours, between about 3.5 hours andabout 4.5 hours, about 1 hour, about 2 hours, about 3 hours, about 4hours, about 5 hours, about 6 hours, less than about 1 hour, less thanabout 2 hours, less than about 3 hours, less than about 4 hours, lessthan about 5 hours, or less than about 6 hours.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include diluting the mixture of coal, sulfuric acid,nitric acid, and the potassium permanganate with water to form asolution. The mixture of coal, sulfuric acid, nitric acid, and thepotassium permanganate with water at a predetermined mixture:waterdilution ratio, such as such as about 1:1, about 1:2, about 1:3, about1:4, about 1:5, about 1:6, about 1:7, or about 1:8.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include mixing the solution, as diluted, with hydrogenperoxide. The hydrogen peroxide can include 10% hydrogen peroxide. Uponmixing the hydrogen peroxide with the solution, the solution turns to ayellow or yellow-green color.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include performing a first centrifugation of the solutionmixed with the hydrogen peroxide. The solution mixed with hydrogenperoxide can be centrifuged for a predetermined period of time, such asat least about 15 minutes, at least about 30 minutes, at least about 45minutes, at least about 60 minutes, between about 15 minutes and about45 minutes, about 15 minutes, about 30 minutes, about 45 minutes, orabout 60 minutes. The solution mixed with hydrogen peroxide can becentrifuged at a predetermined revolutions per minute (RPM) that can bedependent on the centrifuge machine. In some embodiments, the solutionmixed with hydrogen peroxide can be centrifuged at about 500 RPM.

In some embodiments, mixing the coal with at least one of sulfuric acid,nitric acid, potassium permanganate, or hydrogen peroxide to form thecoal oxide can include after performing the first centrifugation,separating supernatant of the solution mixed with the hydrogen peroxidefrom precipitate of the solution mixed with the hydrogen peroxide. Thesupernatant includes the coal oxide, and the precipitate can be waste.Once the supernatant has been separated from the precipitate, thesupernatant can be diluted with water at a predeterminedsupernatant:water dilution ratio. For example, the supernatant can bediluted with water at a dilution ratio of 1:0.5, 1:1, 1:1.5, 1:2, 0.5:1,1.5:1, or 2:1.

At block 730, the coal oxide can be centrifuged during a secondcentrifugation. The coal oxide that is centrifuged can include thedilution of water and coal oxide described above. The coal oxide andwater can be centrifuged for a predetermined period of time, such as atleast about 10 minutes, at least about 15 minutes, at least about 20minutes, at least about 25 minutes, at least about 30 minutes, at leastabout 35 minutes, at least about 40 minutes, between about 10 minutesand about 40 minutes, between about 15 minutes and about 25 minutes,about 15 minutes, about 20 minutes, about 25 minutes, or about 30minutes. The coal oxide and water can be centrifuged at a predeterminedRPM that can be dependent on the centrifuge machine. In someembodiments, the coal oxide and water can be centrifuged at an RPM thatis greater than the RPM of centrifuging of the solution mixed withhydrogen peroxide. For example, the coal oxide and water can becentrifuged at greater than 10,000 RPM, such as about 12,800 RPM.

At block 740, graphene oxide can be collected as precipitate aftercentrifuging the coal oxide and water, and the supernatant of thecentrifugation can be waste. In some cases, block 740 can includesonicating the coal oxide while the coal oxide is in water. In somecases, block 740 can include sonicating graphene oxide that has alreadybeen collected as a precipitate.

At block 750, the graphene oxide can be reduced to form reduced grapheneoxide. Reducing the graphene oxide removes oxygen containing groups fromthe graphene oxide and at least partially recovers the electricalconductivity of the graphene. In some embodiments, reducing the grapheneoxide to form reduced graphene oxide can include at least sonicating thegraphene oxide. The interaction between water and a functional group ofthe graphene oxide promotes exfoliation of the coal oxide layer. Thegraphene oxide can be sonicated for a predetermined amount of time, suchas at least such as at least about 5 minutes, at least about 10 minutes,at least about 15 minutes, at least about 20 minutes, between about 5minutes and about 15 minutes, about 5 minutes, about 10 minutes, about15 minutes, or about 20 minutes. After sonication, the graphene oxideand/or reduced graphene oxide can be analyzed to determine the qualityof the graphene oxide and/or reduced graphene oxide using a Ramanspectroscopy analysis.

In some embodiments, reducing the graphene oxide to form reducedgraphene oxide can include hydrothermally treating the graphene oxide ina par reactor after sonicating the graphene oxide. The graphene oxidecan be hydrothermally treated in the par reactor for a predeterminedamount of time, such as at least about 1 hour, at least about 2 hours,at least about 3 hours, at least about 4 hours, at least about 5 hours,at least about 6 hours between about 1 hours and about 6 hours, betweenabout 3 hours and about 5 hours, between about 3.5 hours and about 4.5hours, about 1 hour, about 2 hours, about 3 hours, about 4 hours, about5 hours, about 6 hours, less than about 1 hour, less than about 2 hours,less than about 3 hours, less than about 4 hours, less than about 5hours, or less than about 6 hours. The graphene oxide can behydrothermally treated in the par reactor at a predeterminedtemperature, such as between about 100° C. and about 300° C., betweenabout 130° C. and about 230° C., between about 170° C. and about 190°C., between about 175° C. and about 185° C., at least about 100° C., atleast about 140° C., at least about 170° C., at least about 180° C., atleast about 190° C., about 170° C., about 175° C., about 180° C., about185 C, or about 190° C. After the graphene oxide is reduced in the parreactor, the resultant solution is clear with jet black flakes andchunks. The jet black flakes and chunks are reduced graphene oxide,which can be confirmed via Raman spectroscopy.

The steps of one or more embodiments of the method 700 surprisinglyproduced improved graphene, as demonstrated in the Raman spectroscopygraphs shown in FIGS. 8A-8D. Specifically, FIG. 8A is a Ramanspectroscopy graph of a sample of raw (non-thermally-treated) Monarchseam coal. The Monarch seam coal has two characteristic Ramanvibrational modes: D-band and G-band. The D-band (1350 cm⁻¹) is thedefect-induced Raman band. The D-band represents the ring breathing modeof sp² hybridized carbon. In order to be active, the ring must beadjacent to a graphene edge or a defect. The G-band (1573 cm⁻¹) is thefirst order Raman spectrum, and corresponds to the in-plane vibration oftwo neighboring carbon atoms on a sp²-hybridized graphene layer. The Gpeak corresponds to the high-frequency E₂ _(g) phonon at F-point.

FIG. 8B is a Raman spectroscopy graph of a sample of thermally-treatedMonarch seam coal. As shown in FIG. 8B, the thermally-treated Monarchseam coal also has two characteristic Raman vibrational modes: D-bandand G-band. FIG. 8C is a Raman spectroscopy graph showing a comparisonof the sample of Monarch seam coal of FIG. 8A to the sample ofthermally-treated Monarch seam coal of FIG. 8B. The comparison indicatesthat the thermally-treated coal has less defects than the raw Monarchseam coal, as the intensity of the D-band (defect-induced Raman mode) isless. This difference in intensity is shown as(I_(G)/I_(D))_(Thermally-Treat)>(I_(G)/I_(D))_(Raw). The comparison alsoindicates that graphitization and graphene formation is better in thethermally-treated coal sample, as the G-Band (graphitic-mode) is moresharp and symmetrical in the thermally-treated coal sample than the rawcoal sample. Accordingly, thermal-treatment of coal according to thisdisclosure improves the graphene formation and reduces the defects inthe coal.

FIG. 8D is a Raman spectroscopy graph of a sample of graphene fromthermally-treated Monarch seam coal. As can be seen in the figure, theintensity includes three sharp peaks at the D-band, G-band, and 2D-band.The sharpness of these peaks, for example as compared to the relativelybroad peaks and overall shape of the graphs of FIGS. 8A-8C indicates thepresence of substantially pure graphene. The resultant graph of FIG. 8Dis indicative of substantially pure graphene nanoplatelets successfullyderived from coal.

The steps of one or more embodiments of the method 700 also surprisinglyproduced graphene oxide at a high yield rate relative to conventionalprocesses for forming graphene from coal. For example, it wassurprisingly observed that the thermally processing coal at atemperature of at least about 300° F. and then forming reduced grapheneoxide from the coal yielded reduced graphene oxide at a yield rate ofbetween approximately 10 weight percent and approximately 20 weightpercent of the coal. The steps of one or more embodiments of method 700can yield reduced graphene oxide at a yield rate of at least about 5weight percent of the coal, at least about 10 weight percent of thecoal, at least about 15 weight percent of the coal, at least about 20weight percent of the coal, at least about 25 weight percent of thecoal, at least about 30 weight percent of the coal, at least about 35weight percent of the coal, at least about 40 weight percent of thecoal, at least about 45 weight percent of the coal, at least about 50weight percent of the coal, between about 2 weight percent and about 50weight percent of the coal, between about 4 weight percent and about 40weight percent of the coal, between about 8 weight percent and about 30weight percent of the coal; between about 10 weight percent and about 20weight percent of the coal, between about 12 weight percent and about 17weight percent of the coal, between about 5 weight percent and about 10weight percent of the coal, between about 10 weight percent and about 15weight percent of the coal, between about 15 weight percent and about 20weight percent of the coal, between about 20 weight percent and about 25weight percent of the coal between about 25 weight percent and about 30weight percent of the coal, between about 30 weight percent and about 35weight percent of the coal, between about 35 weight percent and about 40weight percent of the coal, between about 40 weight percent and about 45weight percent of the coal, between about 45 weight percent and about 50weight percent of the coal, about 5 weight percent of the coal, about 10weight percent of the coal, about 12 weight percent of the coal, about14 weight percent of the coal, about 16 weight percent of the coal,about 18 weight percent of the coal, about 20 weight percent of thecoal, about 22 weight percent of the coal, about 24 weight percent ofthe coal, about 25 weight percent of the coal, about 30 weight percentof the coal, about 35 weight percent of the coal, about 40 weightpercent of the coal, about 45 weight percent of the coal, or about 50weight percent of the coal.

The steps of one or more embodiments of the method 700 also producedgraphene oxide having dopants surprising and useful concentrations. Thedopants in the reduced graphene oxide can include one or more ofantimony, arsenic, barium, beryllium, boron, bromine, cadmium, chlorine,chromium, cobalt, copper, fluorine, lead, lithium, manganese, mercury,molybdenum, nickel, selenium, silver, strontium, thallium, tin,vanadium, zinc, and/or zirconium. In some cases, the one or more dopantspresent in the reduced graphene oxide can produce one or more types ofdefects in the final formed synthetic graphene, such as point defects.In some cases, these defects can enhance or otherwise modify theproperties of the resultant graphene, such as the electrical properties.Accordingly, in some cases, a desired amount of one or more dopants inthe graphene can result in graphene including a desired amount and/ordistribution of defects, such as point defects. The one of more dopantsor impurity atoms present in the graphene oxide can be present inconcentrations that include up to about 0.1 atomic %, up to about 0.5atomic %, up to about 1 atomic %, up to about 2 atomic %, up to about 5atomic %, up to about 10 atomic %, or even up to about 15 atomic % orhigher. In some cases the concentration of any of the one or more dopantor impurity atoms in the graphene oxide can include between about 0.1atomic % and about 15 atomic %, between about 1 atomic % and about 10atomic %, or between about 2 atomic % and about 5 atomic %, for example.

In some embodiments, the concentrations of one or more dopants in thereduced graphene oxide is controlled during the step(s) of thermallyprocessing the coal, as described in greater detail in relation to block710 of the method 700. In some embodiments, one or more dopants can becollected in vapor removed during the thermal processing of the coal andat least partially returned at a predetermined concentration to the coalor graphene oxide during one or more steps of the method 700.

Also disclosed herein are various embodiments of a graphene compositionincluding graphene and one or more dopants. The graphene the graphenecomposition can include one or more of graphene, graphene oxide, and/orreduced graphene oxide in accordance with the method 700. The one ormore dopants in the graphene composition can include at least one ofantimony, arsenic, barium, beryllium, boron, bromine, cadmium, chlorine,chromium, cobalt, copper, fluorine, lead, lithium, manganese, mercury,molybdenum, nickel, selenium, silver, strontium, thallium, tin,vanadium, zinc, and/or zirconium.

The one of more dopants or impurity atoms present in the graphene can bepresent in concentrations that include up to about 0.1 atomic %, up toabout 0.5 atomic %, up to about 1 atomic %, up to about 2 atomic %, upto about 5 atomic %, up to about 10 atomic %, or even up to about 15atomic % or higher. In some cases the concentration of any of the one ormore dopant or impurity atoms in the finally formed synthetic grapheneinclude between about 0.1 atomic % and about 15 atomic %, between about1 atomic % and about 10 atomic %, or between about 2 atomic % and about5 atomic %, for example.

Advanced Carbon Materials

While specific reference has herein been made to the production ofgraphene, the methods and processes described herein can be used toproduce one or more additional advanced carbon materials from coal. Asused herein, the term advanced carbon materials can refer to one or morematerials comprising carbon. In some embodiments, an advanced carbonmaterial can be an allotrope of carbon and can consist essentially ofcarbon. In some embodiments, an advanced carbon material can be a resin,polymer, or other hydrocarbon material.

In some cases, an advanced carbon material can comprise primarily carbonatoms. In some embodiments, an advanced carbon material can comprisecarbon fibers, carbon foams, activated carbon, and/or pyrolyzed carbon.In some embodiments, an advanced carbon material can comprise one ormore allotropes of carbon, for example any allotropes of carbon that areknown in the art or that can be developed in the future. In addition tographene, in some cases, an advanced carbon material can comprisesingle-walled carbon nanotubes, multi-walled carbon nanotubes, carbonmegatubes, carbon nanoribbons, carbon nanobuds, graphite, graphitenano-platelets, quantum dots, and fullerenes, such asbuckminsterfullerene and multi-cored fullerenes.

In some cases, an advanced carbon material can comprise elements inaddition to carbon and can be, for example, a resin, polymer, or otherhydrocarbon material. For example, an advanced carbon material cancomprise polyurethane resins, cyanate ester resins, epoxy resins,methacrylate resins, polyester resins, and others. In some cases, anadvanced carbon material can comprise thermoset or thermoplasticpolymers. In some cases, an advanced carbon material can comprise apolyester, vinyl ester, or nylon polymer.

In some cases, an advanced carbon material can comprise a biologicallyuseful material or biopolymer. That is, in some cases an advanced carbonmaterial can comprise a material including carbon that is used inbiological systems or organisms, that is biocompatible, or that cantypically be produced by a biological organism. For example, in someembodiments an advanced carbon material can be a protein, amino acid,nucleic acid, collagen, chitosan, sugar, or other biological material.In some cases, an advanced carbon material can comprise a porousmaterial, such as a membrane, for use in a biological and/or chemicalprocess. For example, an advanced carbon material can compriseperforated graphene.

In some embodiments where the advanced carbon material can comprisecarbon fibers, the carbon fibers can have different or improved physicalproperties as compared to carbon fibers formed by conventionalprocesses, for example by spinning polyacrylonitrile (PAN). In somecases, carbon fibers produced by the processes described herein can havea higher degree of molecular orientation along the fiber axis thancarbon fibers produced from PAN. In some cases, carbon fibers producedby the processes described herein can have a higher elastic modulus thancarbon fibers produced from PAN. In some cases, carbon fibers producedby the processes described herein can have a higher thermal andelectrical conductivity than carbon fibers produced from PAN. However,in some embodiments, an advanced carbon material can comprise PAN, andthus carbon fibers can be produced from PAN that is formed from coalaccording to the processes described herein.

Applications

The advanced carbon material or materials produced via the methods andprocesses described herein can be used in a wide variety ofapplications. In some cases, the advanced carbon materials produced viathe processing facility described herein can be subjected to furtherprocessing to produce objects, devices, and other products from theadvanced carbon materials. In other embodiments, the advanced carbonmaterials can be distributed to other production facilities for use.Importantly, in some embodiments, the processes described herein canproduce two or more types of advanced carbon materials which can becombined at the processing facility into further products.

In some cases, an advanced carbon material, such as graphene, can befunctionalized and tuned as desired. In some cases, any of the advancedcarbon materials or forms of graphene described herein can be used toadsorb desired elements or compounds or to form functionalized products.For example, in some cases an advanced carbon material producedaccording to the methods described herein can be functionalized toadsorb one or more predetermined materials, elements, and/or substancesfrom water, the atmosphere, or other mediums as desired. In some cases,advanced carbon material produced according to the methods describedherein can adsorb one or more types of rare earth elements produced bycoal processing plants, such as the processing facilities describedherein. In some cases, advanced carbon material produced according tothe methods described herein can adsorb one or more valuablepredetermined elements or compounds from sea water. In some cases,advanced carbon material produced according to the methods describedherein can adsorb CO₂ from the ambient atmosphere.

In some cases, graphene formed according to the methods described hereincan be used as a support or substrate for one or more elements orcompounds. In some cases, these elements or compounds can be utilized toperform desired applications or to have predetermined electrical,chemical, and/or physical properties. For example, in some casesgraphene formed according to the methods described herein can bearranged in layers to serve as a support, scaffold, or substrate for oneor more enzymes that can serve any number of desired functions. In somecases, enzymes supported by a graphene support structure can adsorb CO₂,for example from the ambient environment, to be converted into asecondary product, such as methane.

In some cases, and as described herein, a first amount of pitch can betreated to produce a first advanced carbon material, and a second amountof pitch can be treated to produce a second, different advanced carbonmaterial. In some cases, the first and second advanced carbon materialscan be combined to form a new material and/or produce. For example, thefirst advanced carbon material can comprise carbon fibers and the secondadvanced carbon can comprise a polymer or resin. The first and secondadvanced carbon materials can then be combined via the processingfacility to produce carbon fiber reinforced polymer by any process knownin the art or that can be developed in the future. In some cases, thecarbon fiber reinforced polymer can be formed into a desired structure,for example a part or product as specified by a customer. In someembodiments, an advanced carbon material can be produced via theprocesses described herein and can be combined with one or more othermaterials via the processing facility to produce a composite materialhaving a desired form. For example, the advanced carbon material cancomprise carbon nanotubes. These carbon nanotubes can then be metalizedvia the processing facility to produce a carbon nanotube metal matrixcomposite. In some cases, the carbon nanotube metal matrix composite cancomprise a bulk material, however in some other cases the carbonnanotube metal matrix composite can be formed in a desired shape. Insome cases, a carbon nanotube metal matrix composite can be formed byany processes known in the art or that can be developed in the future,such as via powder metallurgy processes, electrochemical processes, meltprocesses, and others.

In some embodiments where an advanced carbon material can comprise aresin, the resin can be subjected to further processing via theprocessing facility to produce a polymer part or product. In some cases,the resin can be used in a three dimensional printing process to formpolymer structures such as meshes, hollow objects, solid objects, orother products. In some embodiments, a resin produced by the processesdescribed herein can be used in a continuous liquid interface production(CLIP) process as developed by Carbon3D, Inc., to produce a wide varietyof polymer objects via the processing facility. Carbon3D, Inc. uses anumber of different resins to provide end products with selectableproperties via the CLIP process. In some embodiments, the methods andprocesses described herein can be used to produce any of the resins usedin the CLIP process, for example, polyurethane resins, ester resins,epoxy resins, and others. Accordingly, the processing facility cancomprise one or more CLIP printers, such as the M2 Printer developed byCarbon3D, Inc., which can print polymer parts derived directly from coalas described herein. For example, in some embodiments, advanced carbonmaterials produced from coal by the processes described herein can beused in the CLIP process via the processing facility to print dentalproducts which are customized to an individual patient's anatomy. Whilecustom dental products are provided as an example, almost any form ofthree-dimensional object can be produced via the processes describedherein.

For example, in some embodiments where an advanced carbon materialcomprises one or more resins for use in 3D printing, such resins can beused to 3D print products specific to the needs of each customer. Forexample, such 3D printed products can have dimensions corresponding tothe custom measurements of each customer. In some examples, products 3Dprinted using resins produced via the processes described herein caninclude custom helmets, pads, or other protective clothing for use insporting activities and/or combat. In some embodiments, one or more bodyparts of a user or customer can be scanned and the dimensions thereofcan be incorporated into the custom design of the 3D printed product. Insome cases, custom 3D printed products using resins produced via theprocesses described herein can include custom fitted horse shoes and/orsaddles.

In some embodiments, the advanced carbon material resins used in a 3Dprinting process can be modified on site by a user in order to achievethe desired chemical or mechanical properties of the final 3D printedproduct. For example, a first resin produced from coal by the processesdescribed herein can have a first physical property in a final curedstate, such as a first young's modulus. Where a user desires to adjustthis property, they can be direct to add a predetermined amount of asecond resin or other advanced carbon material produced from coal to thefirst resin, where the second resin and amount thereof can be selectedbased on the nature of the adjustment to the first physical property ofthe first resin produced from coal. For example, where a user desires ahigher young's modulus, they can be directed to add a predeterminedamount of a second resin produced from coal in order to raise theyoung's modulus of the first resin. In some cases, this addition can becarried out automatically based on the desired cured material propertiesof the 3D printed object.

In some embodiments, the material properties of a 3D printed objectedcan be varied throughout the volume of the object by utilizing two ormore resins produced form coal according to the processes describedherein that are UV activatable, where each of the two or more resins hasdifferent material properties when cured and each is activated by adifferent wavelength of UV light. For example, in some embodiments afirst resin produced from coal having a first material property, such asa first stiffness, can be activated by a first wavelength of UV light. Asecond resin produced from coal having a second, different materialproperty, such as a second stiffness, can be activated by a second,different wavelength of UV light. The resins can be activated by UVlight to form the product as it is being 3D printed, and the wavelengthof the UV light can be adjusted to vary the material properties of theproduct as it is being printed. For example, UV light having awavelength corresponding to the activation wavelength of the firstresign can be used for those parts of the product where the materialproperties of the first resin are desired. The wavelength can then bevaried or changed to the activation wavelength of the second resin sothat the material properties of the printed object vary from theproperties of the first resin to the properties of the second.

In some embodiments, graphene or other advanced carbon materials can beused in the production of graphene or functionalized graphene ink.Graphene inks can be generated from graphene in accordance with thepresent disclosure and printed onto a source or poured into channel toproduce a graphene-based array.

In some embodiments, a first advanced carbon material produced by theprocesses described herein can be used in a subsequent such process toproduce a second, different advanced carbon material. For example, thefirst advanced carbon material can comprise molecular graphenemembranes. The molecular graphene membranes can then be used in theprocesses described herein to chemically separate products of pyrolysisor liquefaction processes to produce resins. In some cases, this form ofchemical separation via graphene membranes can be more thermallyefficient than other separation processes that are typically employed.These resins in turn can be used in the CLIP process, for example toprint a mesh.

In some embodiments where an advanced carbon material comprisesgraphene, the graphene can be subjected to further treatment via theprocessing facility to form, for example, a graphene sensor. In someembodiments, a graphene sensor can include graphene ink. For example, agraphene sensor can include undoped graphene ink as the circuit to anarea or point that contains doped graphene. In such an embodiment, thedoped graphene area or point can detect, and the undoped graphene inkcan carry a signal to a computing device or user interface. In someembodiments, a graphene sensor can include a flake-based graphenesensor, such as a flake-based graphene biosensor. In such embodiments,some graphene flakes can be doped, and some graphene flakes and/orgraphene ink acting as a circuit will not be doped. These graphenesensors can be used as disposable chips for detecting diseases via ahandheld device. The graphene sensor can be able to immediately detectdiseases, such as Lyme disease or the zika virus from a patient's blood,urine, saliva, or other bodily fluids or biological material, therebyeliminating any need to store blood samples for transportation to a lab.Further, the processes described herein can also be used to print thebody of the hand-held device, and/or a consumable or attachment, such asa microfluidic chamber, for example via the CLIP process.

In some embodiments, advanced carbon materials produced by the processesdescribed herein can be used in a wide variety of other applications.For example, the advanced carbon material can comprise a carbon foamwhich can be used as an electrode in a lithium ion battery. Morespecifically, graphene or reduced graphene oxide produced by theprocesses described herein can be used in an electrode in a battery. Thegraphene or reduced graphene oxide produced by the processes describedherein used in an electrode in a battery can include one or more of thedopants described herein at any of the amounts described herein. In somecases, the advanced carbon material can comprise activated carbon thatcan be used in an atmospheric CO₂ recapture process. In some cases, theatmospheric CO₂ recapture process can be carried out via the processingfacility and captured CO₂ can be used in the processes described herein.

In some embodiments, advanced carbon materials, such as graphene, formedaccording to the processes described herein can be used to produce solarpanels. In some cases these solar panels can have greater efficienciesthan other conventionally produced solar panels. In some embodiments,advanced carbon materials formed according to the processes describedherein can be used as precursors in electrospinning processes. Forexample, advanced carbon materials can be used to electrospin scaffoldsor other structures having micron level resolution. In some cases theadvanced carbon materials used in electrospinning can be biomaterialsproduced from coal according to the processes described herein. In someembodiments advanced carbon materials can be used to produce gels, forexample medical grade gels such as hydrogels or silicone gels.

In some embodiments, one or more advanced carbon materials produced fromcoal according to the processes described herein can be used asautomotive grade materials in the production of cars, trucks, or otherautomobiles. For example, carbon fibers, resins, and/or CFRPs can beused as automotive frames, structural components, body panels, engineblocks, and/or other components. In some cases, the components can be 3Dprinted and can be custom designed according to a user's preferences.

In some embodiments, one or more advanced carbon materials produced fromcoal according to the processes described herein can be used to formproducts for use in chemical or biological processes, suchchromatography columns, membranes, and filters. In some cases,chromatography columns, membranes, and/or filters can be 3D printed fromone or more advanced carbon materials produced from coal according tothe processes described herein. In some cases, the chromatographycolumns, membranes, and/or filters can be used to isolate or removeantibodies, bacteria, parasites, and/or heavy metals from varioussolutions.

In some embodiments, reinforced graphene can be produced in accordancewith the disclosures of the present application. The reinforced grapheneincludes graphene and nanotubes. Advantageously, graphene having one ormore dopants described herein can chemically bond with nanotubes havinganother dopant. This chemical bond can form between the carbon nanotubeand the graphene sheet, and can allow the repetitive layers of graphenesheets to form a graphene filter. Graphene filters in accordance withthe present disclosure also can be formed using chemical linkers. Forexample, different dopant metals on each end of chemical linkers allowthe chemical linkers to be directional and control the space between thegraphene sheets, the graphene sheets being pre-doped with reactivedopants that are different to the chemical linkers.

In some embodiments, one or more advanced carbon materials produced fromcoal according to the processes described herein can be used to formcircuit boards. For example, a carbon foam produced from coal asdescribed herein can be 3D printed to form a circuit board. In somecases a carbon foam circuit board can have superior electrical andthermal properties to typical printed circuit boards. In someembodiments, one or more advanced carbon materials produced from coalaccording to the processes described herein can be synthetic grapheneand can be used in a variety of electronic applications, for example informing quantum dots and in computer chips. In some cases, graphene canbe used to produce biosensors that can be capable of isolating and/oridentifying any number of biologically active molecules or substances,such as disease biomarkers or viruses.

In some embodiments, one or more advanced carbon materials produced fromcoal according to the processes described herein can include compositematerials, such as metals or concrete including carbon fibers, graphene,or other advanced carbon materials. In some examples, metal includingone or more advanced carbon materials such as graphene, carbon fibers,or carbon nanotubes can be 3D printed. In some examples, carbon fiber orCFRPs produced from coal as described herein can be used as rebar inconcrete or can be used as other construction or building materials.

Unless otherwise indicated, all numbers or expressions, such as thoseexpressing dimensions, physical characteristics, etc., used in thespecification (other than the claims) are understood as modified in allinstances by the term “approximately.” At the very least, and not as anattempt to limit the application of the doctrine of equivalents to theclaims, each numerical parameter recited in the specification or claimswhich is modified by the term “approximately” should at least beconstrued in light of the number of recited significant digits and byapplying ordinary rounding techniques.

In addition, all ranges disclosed herein are to be understood toencompass and provide support for claims that recite any and allsubranges or any and all individual values subsumed therein. Forexample, a stated range of 1 to 10 should be considered to include andprovide support for claims that recite any and all subranges orindividual values that are between and/or inclusive of the minimum valueof 1 and the maximum value of 10; that is, all subranges beginning witha minimum value of 1 or more and ending with a maximum value of 10 orless (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1to 10 (e.g., 3, 5.8, 9.9994, and so forth).

We claim:
 1. A method of producing reduced graphene oxide from coal, themethod comprising: thermally processing coal at a temperature of atleast about 300° F.; oxidizing the thermally processed coal to form coaloxide; and forming reduced graphene oxide from the coal oxide, thereduced graphene oxide comprising a predetermined concentration of lessthan about 15 atomic % of one or more impurity atoms.
 2. The method ofclaim 1, wherein forming reduced graphene oxide from the coal oxidecomprises: centrifuging the coal oxide; collecting precipitate from thecoal oxide after centrifuging, the precipitate comprising grapheneoxide; and reducing the graphene oxide to form reduced graphene oxide.3. The method of claim 1, wherein oxidizing the coal to form a coaloxide comprises mixing the coal with at least one of sulfuric acid,nitric acid, or potassium permanganate, or hydrogen peroxide to form thecoal oxide.
 4. The method of claim 3, wherein mixing the coal with atleast one of sulfuric acid, nitric acid, potassium permanganate, orhydrogen peroxide to form the coal oxide comprises: mixing the coal withat least one of sulfuric acid and nitric acid; stirring the coal mixedwith at least one of the sulfuric acid and the nitric acid; mixingpotassium permanganate to the coal mixed with at least one of thesulfuric acid and the nitric acid; stirring the coal mixed with thepotassium permanganate and at least one of the sulfuric acid and thenitric acid; diluting, with water, the coal mixed with the potassiumpermanganate and at least one of the sulfuric acid and the nitric acidto form a solution; mixing the solution with hydrogen peroxide;performing a first centrifugation of the solution mixed with thehydrogen peroxide; and after performing the first centrifugation,separating a supernatant of the solution mixed with the hydrogenperoxide from precipitate of the solution mixed with the hydrogenperoxide, the supernatant comprising the coal oxide.
 5. The method ofclaim 2, further comprising diluting, with water, the coal oxide beforecentrifuging the coal oxide.
 6. The method of claim 2, wherein reducingthe graphene oxide to form reduced graphene oxide comprises: sonicatingthe graphene oxide; and hydrothermally treating the graphene oxide in apar reactor after sonicating the graphene oxide.
 7. The method of claim1, wherein thermally processing coal at a temperature of at least about300° F. comprises: heating the coal to a first temperature not to exceed350° F.; transferring the coal to a mercury removal reactor; heating thecoal in the mercury removal reactor to a second temperature of at least500° F.; and contacting the coal with an inert gas to remove at least aportion of mercury present in the coal.
 8. The method of claim 1,wherein forming reduced graphene oxide from the coal oxide comprisesforming the reduced graphene oxide from the coal oxide at a reducedgraphene oxide yield rate of between approximately 10 weight % andapproximately 20 weight % of the coal.
 9. The method of claim 1, whereinthe one or more impurity atoms comprise one or more of cadmium,selenium, boron, nitrogen, or silicon.
 10. The method of claim 9,wherein the one or more impurity atoms comprise one or more of boron,nitrogen, or silicon.
 11. The method of claim 1, wherein thepredetermined concentration of one or more impurity atoms is betweenabout 0.1 atomic % and about 10 atomic %.
 12. A synthetic grapheneformed from an amount of coal, the synthetic graphene comprising: apredetermined concentration between about 0.1 atomic % and about 15atomic % of dopant atoms, the dopant atoms derived from the amount ofcoal.
 13. The synthetic graphene of claim 12, wherein the dopant atomscomprise one or more of cadmium, selenium, boron, nitrogen, or silicon.14. The synthetic graphene of claim 13, wherein the dopant atomscomprise one or more of boron, nitrogen, or silicon.
 15. The syntheticgraphene of claim 12, further comprising a predetermined concentrationof point defects due to the one or more dopant atoms.
 16. The syntheticgraphene of claim 12, wherein the predetermined concentration of dopantatoms is between about 0.1 atomic % and about 5 atomic %.
 17. Asynthetic reduced graphene oxide formed from an amount of coal, thesynthetic reduced graphene oxide comprising: a predeterminedconcentration between about 0.1 atomic % and about 15 atomic % of one ormore impurity atoms, the one or more impurity atoms derived from theamount of coal.
 18. The synthetic reduced graphene oxide of claim 17,wherein the one or more impurity atoms comprise antimony, arsenic,barium, beryllium, boron, bromine, cadmium, chlorine, chromium, cobalt,copper, fluorine, lead, lithium, manganese, mercury, molybdenum, nickel,selenium, silver, strontium, thallium, tin, vanadium, zinc, orzirconium.
 19. The synthetic reduced graphene oxide of claim 17, whereinthe predetermined concentration of impurity atoms is between about 0.1atomic % and about 5 atomic %.
 20. The synthetic reduced graphene oxideof claim 17, wherein the synthetic reduced graphene oxide comprises anelectrode of a battery.